﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp4
{
    class Program
    {
        static void Main(string[] args)
        {
            for (int h = 0; h < 20; h++)
            {
                if (h == 3)
                {
                    continue;
                }

                Console.WriteLine("第{0}次", h);
                Console.WriteLine("第{0}次", h);
            }
            

                int q = int.Parse(Console.ReadLine());
                switch (q / 10)
                {
                    case 10:
                    case 9:
                        Console.WriteLine("优秀");
                        break;
                    case 8:
                        Console.WriteLine("优秀");
                        break;
                }

                var t = true;
                var f = !true;
                var result = 10 % 2 == 0 ? "偶数" : Convert.ToString(0);
                var b = 3;
                var c = 3;
                var r1 = ++b;
                var r2 = c++;
                var x = int.TryParse("123", out int res);
                if (x)
                {
                    Console.WriteLine("转换成功，值为：" + res.ToString());
                }
                else
                {
                    Console.WriteLine("转换失败");
                }
                Console.WriteLine(r1);
                Console.WriteLine(r2);

                int sum = 0, i, j;
                for (i = 1; i < 4; i++)
                    for (j = 1; j < 5; j++) sum = i + j;
                Console.WriteLine("%d\n", sum);

            }
        }
    }
